Hydraulic modelling of sewage exfiltration

摘要

Exfiltration of waste water in sewer networks represents a potential danger for the soil and thenaquifer. Various modelling approaches have been proposed to quantify sewerage exfiltration andnits spatial and temporal variation. Common models are based on the law of Darcy, extended by anmore or less detailed consideration of the expansion of leaks, the characteristics of the soil andnthe colmation layer. In the paper investigations are introduced, which are focused on the actualnwater content of the soil and its influence on exfiltration rates. Modelling results with HYDRUS 1Dnshow, that under unsaturated conditions initial exfiltration rates are increased compared tonsaturated conditions. In experiments it was found, that the matrix potential increases thentightness of the colmation layer. Further a colmation model was deduced, which allows thencalculation of the thickness and conductivity of the colmation layer.